ABB GFD233A 3BHE022294R0101 Excitation controller module is a device used to control the excitation current of an alternator. Excitation current is the current flowing through the generator's field winding, and it is this current that determines the strength of the generator's magnetic field. The strength of the magnetic field in turn determines the magnitude of the voltage induced in the generator armature winding.

The GFD233A is a three-phase brushless excitation controller designed for generators with rated voltages up to 690V. It is a compact and lightweight unit that is easy to install and maintain. The GFD233A has many features that make it a versatile and reliable excitation controller, including: automatic voltage regulation (AVR), soft start and soft stop, overcurrent protection, short circuit protection, and ground fault protection.